diff --git a/scripts/map_tokens.py b/scripts/map_tokens.py
new file mode 100644
index 00000000..327f4651
--- /dev/null
+++ b/scripts/map_tokens.py
@@ -0,0 +1,22 @@
+#!/usr/bin/env python3
+
+import argparse
+import pickle
+
+from delphi.eval.token_map import token_map
+from delphi.eval.utils import load_validation_dataset
+
+if __name__ == "__main__":
+    parser = argparse.ArgumentParser(description="")
+    parser.add_argument(
+        "dataset_name", help="Dataset from huggingface to run token_map on"
+    )
+    parser.add_argument("--output", help="Output file name", default="token_map.pkl")
+    args = parser.parse_args()
+
+    dataset = load_validation_dataset(args.dataset_name)
+
+    mapping = token_map(dataset)
+
+    with open(f"data/{args.output}", "wb") as f:
+        pickle.dump(mapping, file=f)
diff --git a/src/delphi/eval/token_map.py b/src/delphi/eval/token_map.py
new file mode 100644
index 00000000..17e8e2ca
--- /dev/null
+++ b/src/delphi/eval/token_map.py
@@ -0,0 +1,18 @@
+import os
+from typing import cast
+
+from datasets import Dataset
+
+
+def token_map(
+    tokenized_dataset: Dataset,
+) -> dict[int, list[tuple[int, int]]]:
+    """Return a mapping of tokens to their (prompt_idx, token_idx) locations in the tokenized_dataset."""
+
+    mapping = {}
+    for prompt_idx, prompt in enumerate(tokenized_dataset):
+        prompt = cast(dict, prompt)
+        for token_idx, token in enumerate(prompt["tokens"]):
+            mapping.setdefault(token, []).append((prompt_idx, token_idx))
+
+    return mapping
diff --git a/tests/eval/test_token_map.py b/tests/eval/test_token_map.py
new file mode 100644
index 00000000..5a276080
--- /dev/null
+++ b/tests/eval/test_token_map.py
@@ -0,0 +1,48 @@
+import pytest
+from datasets import Dataset
+
+from delphi.eval.token_map import token_map
+
+
+def test_token_map():
+    tokenized_dataset = Dataset.from_dict(
+        {
+            "tokens": [
+                [0, 1, 2, 3, 4, 5, 0, 6, 7],
+                [0, 1, 2, 3, 4, 5, 0, 6, 7],
+                [0, 1, 2, 3, 4, 5, 0, 6, 7],
+            ]
+        }
+    )
+    mapping = token_map(tokenized_dataset)
+    assert mapping == {
+        0: [(0, 0), (0, 6), (1, 0), (1, 6), (2, 0), (2, 6)],
+        1: [(0, 1), (1, 1), (2, 1)],
+        2: [(0, 2), (1, 2), (2, 2)],
+        3: [(0, 3), (1, 3), (2, 3)],
+        4: [(0, 4), (1, 4), (2, 4)],
+        5: [(0, 5), (1, 5), (2, 5)],
+        6: [(0, 7), (1, 7), (2, 7)],
+        7: [(0, 8), (1, 8), (2, 8)],
+    }
+
+    # fmt: off
+    tokenized_dataset = Dataset.from_dict(
+        { # one really long prompt
+            "tokens": [
+                [0, 1, 2, 3, 4, 5, 0, 6, 7, 0, 1, 2, 3, 4, 5, 0, 6, 7, 0, 1, 2, 3, 4, 5, 0, 6, 7]
+            ]
+        }
+    )
+    # fmt: on
+    mapping = token_map(tokenized_dataset)
+    assert mapping == {
+        0: [(0, 0), (0, 6), (0, 9), (0, 15), (0, 18), (0, 24)],
+        1: [(0, 1), (0, 10), (0, 19)],
+        2: [(0, 2), (0, 11), (0, 20)],
+        3: [(0, 3), (0, 12), (0, 21)],
+        4: [(0, 4), (0, 13), (0, 22)],
+        5: [(0, 5), (0, 14), (0, 23)],
+        6: [(0, 7), (0, 16), (0, 25)],
+        7: [(0, 8), (0, 17), (0, 26)],
+    }